The Initial Volume of a Sample Is 100 μL $\frac{(400 \mu \mathrm{L})\left(\frac{25 \mu g}{\mathrm{~mL}}\right)}{100 \mu \mathrm{L}}$

question 4

Multiple Choice

The initial volume of a sample is 100 μL.It is diluted with saline by a factor of 4.The final volume is 400 μL.Testing the diluted sample finds an analyte concentration of 25 μg/mL.Which of the following expressions can be used to calculate the initial analyte concentration of this sample?

• A) \( \frac{(400 \mu \mathrm{L})\left(\frac{25 \mu g}{\mathrm{~mL}}\right)}{100 \mu \mathrm{L}} \)
• B) \( \frac{(100 \mu L)\left(\frac{25 \mu g}{m L}\right)}{400 \mu L} \)
• C) \( \frac{(400 \mu \mathrm{L})(100 \mu \mathrm{L})}{\frac{25 \mu \mathrm{g}}{\mathrm{mL}}} \)
• D) \( \frac{\text { (2) }\left(\frac{25 \mu g}{m L}\right)}{400 \mu \mathrm{L}} \)

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Definitions:

Normal Balance

A reiteration with different wording: The typical side (debit or credit) an account is expected to have, based on standard accounting rules.

Account Category

A classification used in accounting to organize financial transactions, such as assets, liabilities, equity, revenue, and expenses.

Net Sales

The total revenue from sales transactions after deducting returns, allowances, and discounts.

Discount Period

A specified period within which a buyer can pay less than the full amount due by taking advantage of a discount offered by the seller.